Device for transforming the crystalline structure of wires



y F. KOREF DEVICE FOR TRANSFORMING THE CRYSTALLINE STRUCTURE OF WIRES Filed July 6. 1922 Inventor His Jqttofne g Neverthe1ess,'it is difficult to avoid the va-" Patented May 17, 1927.

T D STATES PATENT OFFICE.

FRITZ KOREF, 0F BERLIN, GERMANY, ASSIGNOR TO GENERAL ELECTRIC COMPANY, A CORPORATION OF-NEW YORK..

' DEVICE FOR 'rmmsroammc THE CBYSTALLINE STRUCTURE or WIRES.

Application filed July 6, 1922, Serial-No. 573,163, and in Germany July 13, 1921.

are moved continuously between two cur-f rent-supplying members and the part situated between the members is broughtto an extremely high temperature by the electric current. The' currents'up'p'ly'ing members utilized for. this purpose have previously been mercury contacts." At the high-temperature of the'wires', filaments, and the like;

the mercury contacts must "be greatly cooled:

, porization of the mercury'and its deposition "on the cooler parts'o'f the apparatus.-

tionis dispensedw'ith and provision is made; by'reason of the shape' 'of the parts that'come-T in contact withthe' wire-,3 or" otherwise as which 'is 'bein movedh' it'ghasbeei'i thatfwh'en'sucli a current-supply member is employed at the admission side of'thewire, filament or the like which -is being 'moved, the transformation of the structure into the";

structure desired is much more perfect and uniform, The reasons for this will be under-- stood if the progress of the transformation is more closely considered. The transformation consists in a continuous crystallization,-

the arriving structural elements, that is, the

fresh portions of the Wire which enter the circuit, being absorbed by the larger crystal proceeds more slowly than the speed of feed-1 ing the wire, which zone must bepassed through as quickly'as possible. Moreover the progress of the rise of temperature in T My invention I will ;drogen and nitrogen.

such as rolls 4, moves the wlre 5, which is to chamber through slots in the cover 2.

the wire being moved must always be the same after passing the place of contact, so that the point where the crystallization sets in, is always the same distance from the place of contact. Even with variations of fractions of a millimeter, the progressive crystallization might easily be interrupted, and this would result in defects, for example places'of coarse-crystalline structure. These conditions of a rapid and persisting rise of temperature are fulfilled in the device of the invention in a much more perfect manner than in the case of the use of the'mercurr contacts heretofore used. After passing the cooled-mercury contacts, the rise of temperature extends over a wide range, namely from about 200 to 300 degrees as a lower limit up to the temperature of transformation, which The device'ofthe present-invention is free from this difficulty, Accordingto the inven-g tion the current-supplying members c nsisq as to the portions that come, incontalctiwvitlr the wireiofextremel ,fhigh' tusi'ng materials,-

e. Tlie cooling'opera-=" that is,"'about 1500 to 1800 degrees The rise of temperaturetherefore in this caseextends 4. a be ee two "points much nearer together described hereinafter," that ithe'se' parts asl sume'lquite a temperature, a bright 'red glow for example; Thisfisiparticularly true of the current-supplying"member which' is situated attheadmission side'bflthe' wire is about 2300 to 2500 degrees. But when contact-points of extremelyuhigh fusing ma- 'perature where the speed: of crystallization ='in"the-'-'wire finally begins to'assume values,

and therefore is more readily preserved from disturbances;

of device embodying my invention; F ig. 2 in as ide view of another form; Fig. is an end viewofthe left half section of. the derice of Fig. '2. I e l The particular apparatus illustrated in Fig. 1 comprises a base land a removable cover 2 cooperating with the base to form -a substantially closed chamber into which inert gas, such as forming gas, can be introduced through an inlet 3, and allowed .to escap'e through any suitablevents. Forming gas, ofcourse, consists of a mixture of hy- Feeding mechanism,

be transformed, longitudinally through the Current for heating a short section of the wire 5 in the chamber is furnished from a supply circuit 6 which is connected to Contacts mounted in the chamber and spaced apart at the proper distance.

be better understood by reference to the accompanying drawing in Which I have illustrated certain embodif ments of my invention and in which Fig. 1 is a longitudinal section through one form -of a; pitoted ofi -scald-beam 10=iand.its;p1fesfsurezon ithe lower Vblbck may be regulated by.

which icountenveigli -justable. .i. 1

In It): sui-table' construction the deyfice in accordance with my invention the contacts or current supply members for supplying the heating current to the wire-"o consist-of two blocks 7 and 8 of extrem'ly hi' gh f'using rnetaLwhicll are pressed together b a light spring? agai'nsfithe wire5'whith'ismove'd forward hetween tl 1em I-he powenof the spring will be 'so selected-that it is just enough to maintain continuous :contact and to-avoid. unnecessary; fr-ictio n. on .the moving the point of' Icontact toknifefedge which is arranged,trans erseIyI-t -the; direction .of movement of the wire -5.. 'I he advantage of this form! of; contactgis; that the; heat conduetion; is reducedso-i'thatlthe;pointfcontact assumes ,ahigherqtemperature than is the case with aacylindriealblopki- The. pre'ssingvtogethen ofthcjtwoblpcks 7 and-8- by spring powenrsuchms the spring 9 is' recommended in casesv =the :w ir;e is being-movediimk PGIPGDdIOUIEIUdIIGCtIQD,

Ifthe: movement; foivthe' Waite vine Bl 119 'zontal direction sdme'mtlier; construction may that the-desired amountof current may be passed through the wire'contact 12. In this way'it becomes possible in a simpler manmen to bring-the point'o'f contact of theiwire 5 -wit-li' the heated wire contact 12 to any desired temperature. This latter temperature is so "chosen" that-at" that-temperature, crystallization does.not. ta ke placc in the wire S'that is being moved over the contact. The" choice. of. ahigher temperature is-prohibitedfor the. reason that the wires 5 and 12 would then easily-adhere. As in'dicated in--I ig."2, this construction will-'be chosen only-for. the leading; contact which engages {the wirez'ras it enters the zone of incandesconce, while-at the exit side'the simpler construction oft the. contacts, such as 'the Julie-edged blocks 7 and'S. will' be siifiident. in order tounaintaingood electrical contact between the wire contact 12.1 proiide-apresser'H of ;.-som e highi-fusing moor such. as .tung'sten ;w ire= bent into .the' formof a I yoke. and carb-ried.on a,pivotedg fork 15 proi'ide'd'with a counterweight 16 by means of-' whi'clfthe' prcssu re exerted by .the presser 14 to hold the wire 5' against-thei heated wire contact .12 canbe regulated as desired.

I- wish ihundeistood that the. temperature t re o e iggwhat.Lclainras-mewand desire tosec'ure --by;Let ters Batent of the United States, is,-

apparatus for 't'rans'forming tl1e "ire 5 'a-ndthe heated scaletoiwhi'ch lf. referinithis specification is beis leeted (and-1 twm 1516 158 rand-8 may: :orystall ine structure of wires. andi the like i no be arrangedz one. abovei-the 1 ;o,ther perpen upper block 8 is, freeg to :move-sand: presses friction 'Eto theleash possible: mount: :Whicli ismecessirry for gofid elctribli qonfact the 7 p said contacts to-heatthe portion ofthe wire --between them.

means of a suitablecounterw'eight 11; arranged-on the wother endhof the beam 10 timay rifi desired, be"-ad- "ltzhas' in many cases-beenIfound-Z-to -be.

; particiilarly advantageousto .adoptanother- 'cons'truction in which instead of; the two r. or one of-zthe: tw'o';b1oeks;.7= Bd== 9; C ntact 'wire or istrip.-.-12- of --extremely;highfusing meta-1; preferhblyi. tungsten; 1 arranged; trans-.-

- versely to therdirection'of moYement of: the

wire is employed-e and this =wire contact- 12 is-heated-electrically: For-i example,v as illustrated in;- E-igs.-- 2* and 3 the wire contact 12- whichiszmadeeof comparatively heavy tungsten wirc,--is;mounteclIonfpedcstals 13 secured-to the hasel" and --1nsu-lated'- from each other but connected to the source ot-current 6, as shown diagrammatically'iu Fig. 2, so

cornposed 1 of high 1 fusing metals su'ch as tungstenz by as cont nuous process. compris- .-'.-i ngj-the' heatingof. aportionof. the wire to high- -incandescence, the combination. with contacts of wery. high fusing' material, such as tungstenzor molyhdenuinmndadapted to .1 befconnected-to a source oficurrent, of nieans for guiding the wireto be transformed over 7 -2.- In-.- apparatus --for. transforming the q 'ystalline structure of small-crystal tungsten -wiresbye-lectrieal. heating, the combinatiomof two' sets of contacts -vea ch consistingof= two blocksof eryfhigh fusing material and resilient meansfor ,pressing one towar'd thehother, and 9 means" forv passing the wireto-be transformed: through said contacts-and between .said blocks whereby J'cu rrent may -pass through said wire.

3.";In apparatus-10r- .transforming .the

=crystalline structure of tungsten wire-by electrical-heating, the combination of electrical contacts. eaci-r.c(m\prisin; a palr: oi blocks mounted one above-the otherto, perlimit the uppenhlool; to more freely toward the-lowel onc by gravity, and means 5m: passing the wire to he. transformer] hctwccn said contacts and lmtu'een said lilorks to pass current through said wire.

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4. In apparatus for transforming the crystalline structure of tungsten wire by electrical heating, the combination of an electrical contact comprising two blocks mounted one above the other with the upper block free to move toward the lower, an adjustable counterweight for regulating the pressure of the upper block on the lower one, and means for passing a wire between said blocks to make electrical contact therewith.

5. In apparatus for transforming the crystalline structure of tungsten Wire, the combination of'contacts for passing current through said wire, one of said contacts comprising two blocks and means for pressing one toward the other, one of said blocks being composed of a refractory material of poor heat conductivity such as thorium oxide, and means for passing the wire to be transformed between said contacts and between said blocks.

6. In apparatus for transforming the crystalline structure of tungsten Wires by electrical heating, the combination of two contacts,one composed of two knife edged blocks one mounted to move freely toward the other to bring said knife edgcsinto engagement, and means for moving a wire through said contacts and between said knife edge in a direction transverse to said knife edges. g l

7. In apparatus for transforming the crystalline structure ofv tungsten wires .by electrical heating, the ,combination with means for moving "longitudinally the wire to be transformed,-1 a pair of contacts -mounted to engage said wire and spaced 1 apart'tov heat a portion of said wire to high incandescence and maintain a zone of high temperature, one of said contacts comprising an electrically heated wire or strip of very high fusing metal such as tungsten arranged transversely to the direction of .movement to the-wire to be transformed and in engagment with it.

8. In a device for transforming the structure of a strip of a refractory metal into 1 macro-crystalline form, in combination a macro-crystalline form, in combination a pair of contacts, one being of a refractory metal, between which contacts the strip is adapted to be drawn, and a source of current connected to said contacts for heating the strip between the contacts and for heating one of the contacts to a temperature ator in the neighborhood of red heat, one of said contacts comprising two elements between which the metal passes while being drawn, and means for yieldingly holding one of said elements against the metal.

10. In a device for transforming the structure of a strip of a refractory metal into macro-crystalline form, in combination a pair of contacts, one being of a refractory metal, between which contacts the strip is adapted to be drawn, and a source of current connected to said contacts for heating the strip between the contacts and for heating one of the contacts to a temperature at or in the neighborhood of red heat, said contacts located in a non-liquid surrounding medium.

11. The process of transforming a refractory metal into macro-crystalline form which consists in moving the metal across two contacts which are the terminals of a source of potential, and thereby heating the metal to a temperature corresponding to red heat and thereby also heating one of the contacts to prevent the metal from being chilled.

12. The process of transforming arefractory metal into macrocrystalline form which consists in subjecting the metal to a heating electric current between two terminals of a source of current and thereby heating the metal to a red heat and at the same time heating one of said terminals to assist in maintaining the temperature of the metal.

13. The process of transforming a refractory metal from one form to another, which consists in drawing the metal across the terminals of an electric circuit and thereby heating the metal and in maintaining the temperature of the wire as it passes from one terminal to the other at substantially the same temperature, the terminal at which the metal leaves the circuit being at a temperature approximately equal to that of the metal as it leaves the circuit.

14. The process of transforming a wire of refractory metal into a macro-crystalline form which consists in subjecting the wire to an electric current to thereby heat the wire by drawing the wire across the terminals of an electric circuit and in maintaining the temperature at the point of crystallization, the terminal at which the metal leaves the circuit being a solid and being maintained at a temperature approximately equal to that of the heated metal as it leaves the circuit.

In witness whereof, I have hereunto set my hand this 15th day of June, 1922.

FRITZ KOREF. 

